Acoustic downhole tool with rubber boot protected by expandable sleeve

ABSTRACT

A downhole tool having a body, a transducer within the body, and an opening formed through a sidewall of the body. The opening provides a port through which the transducer can communicate from within the body. An elastomeric boot in the body covers the opening and is a barrier that prevents fluid ingress into the downhole tool. An expandable sleeve envelopes the elastomeric boot and provides support that limits bulging of the elastomeric boot from within the body through adjacent openings in the body. An example sleeve is made from elongated members woven into a tubular.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of co-pending U.S.Provisional Application Ser. No. 61/305,839, filed Feb. 18, 2010, thefull disclosure of which is hereby incorporated by reference herein.

BACKGROUND

1. Field of Invention

The invention relates generally to the field of downhole acousticmeasurement. More specifically, the present invention relates to adownhole tool having a rubber boot covered by an expandable sleeve.

2. Description of Prior Art

FIG. 1 illustrates a side partial sectional view of a downhole tool 10deployed on wireline 14 within a wellbore 12. The downhole tool 10 isused for interrogating a formation 16 adjacent the wellbore 12,gathering information about the formation 16, and either storing ortransmitting the information via the wireline 14 to a surface truck 18shown controlling the downhole tool 10. In this prior art example, thedownhole tool 10 includes an elongated body 20 for housing componentswithin the downhole tool 10. One example of a component shown is atransducer 22; which in this example is illustrated as an acoustictransmitter and emitting an acoustic signal from within an opening 26formed through a side wall of the body 20. The signal propagates intothe formation 16; a portion of the acoustic signal reflects back towardsthe downhole tool 10. A second transducer 24 is shown, also housedwithin the body 20, and in this example is an acoustic receiverconfigured for receiving the acoustic signal reflecting from theformation 16. A corresponding opening 28 is formed through the body 20so the transducer 24 can receive the reflected signal.

A portion of the logging tool 10 is shown in sectional view toillustrate boots 30, 32 within the tool that cover the openings 26, 28.The hoots 30, 32 are typically made from an elastomeric material, suchas rubber or another type of flexible polymer. Often, dielectric fluid,such as silicone, fills the inside of the body 20 for electricallyinsulating components within the body 20. Because fluids in the wellbore12 typically include conductive materials damaging to components withinthe body 20; the boots 30, 32 form a harrier for preventing wellborefluid ingress into the body 20. Also, as wellbore pressure overcomesdielectric fluid pressure, wellbore pressure through the openings 26, 28causes the pliable boots 30, 32 to bow inward and impinge the dielectricfluid; thereby equalizing wellbore and dielectric fluid pressure.

FIG. 2 illustrates a side partial sectional view of a portion of thedownhole tool 10 of FIG. 1. In this view, the tool 10 is being raisedfrom within the wellbore 12 after having been immersed in wellborefluids. While immersed downhole, wellbore fluid constituents, such aslower molecular weight compounds, can migrate through the boots 30, 32and become trapped within the boots 30, 32 in the body 20. Raising thedownhole tool 10 toward the surface reduces the hydrostatic pressureapplied to the boots 30, 32 and dielectric fluid to allow lightermolecular weight fluids to expand or vaporize. As the trapped fluidsexpand and/or vaporize, the hoots 30, 32 can bow outward through theopening 26, 28 and into contact with the inner walls of the wellbore 12.Contact against the wall of the wellbore 12 may damage the boots 30, 32.Additionally, once removed from within the wellbore 12, the trapped highpressure fluid within the boot 30, 32 must be vented so the tool 10 canbe serviced. This can present added turnaround time and steps.

SUMMARY OF INVENTION

Disclosed herein is a downhole tool insertable within a wellbore. In anexample embodiment the downhole tool includes a housing, a space in thehousing, and an opening that is formed through a sidewall of thehousing. The tool further includes a barrier between the opening and thespace a membrane. A series of elongate members are arranged on a side ofthe membrane that faces the opening. The members restrain the membranefrom bulging through the space when pressure in the space exceedspressure ambient to the housing. A transducer may be included within thehousing, example transducers are acoustic transmitters, acousticreceivers, and those that can transmit and receive. In an exampleembodiment, the transducer acoustically communicates from within thehousing and through the membrane and the series of elongate members. Inan example embodiment, the barrier is formed from an elastomericmaterial and formed into a sleevelike configuration and wherein theelongate members define a sleeve that circumscribes the barrier. In anexample embodiment, a mandrel is in the space and a coupling anchors thesleeve and barrier to the mandrel. In an example embodiment, the toolmay further include a plurality of openings from through the sidewall ofthe housing, a barrier between each of the openings and the space,wherein each of barrier comprises a membrane, and a series of elongatemembers on the surface of each membrane facing the opening. In anexample embodiment, at least some of the elongate members intersect someof the other elongate members to define a mesh.

Also disclosed herein is a method of wellbore operations. In an exampleembodiment, the method includes providing a downhole tool made up of ahousing with an inside space and an opening through a sidewall of thehousing. A barrier is set between the inside space and the openings. Themethod includes shielding the barrier from direct contact with aborehole wall by applying a series of elongate members between thebarrier and the opening. Thus when the tool is inserted into thewellbore the barrier is protected from contact. The barrier elongatemembers also prevent the barrier from ballooning outward by retainingthe barrier within the housing when the pressure in the space exceedspressure ambient to the housing. The downhole tool is deployed in thewellbore. In an example embodiment, the elongate members are arranged ina mesh-like configuration and intertwined to form a cohesive member. Inan example embodiment, the barrier and the cohesive member are tubularmembers; the method can then further include clamping the barrier andcohesive member to a mandrel within the housing. In an exampleembodiment, the method further includes acoustically communicating fromwithin the housing and through the barrier and elongate members. In anexample embodiment, acoustically communicating includes actuating atransducer within the housing. In an example embodiment, the transducercan be an acoustic transmitter, an acoustic receiver, or can transmitand receive.

BRIEF DESCRIPTION OF DRAWINGS

Some of the features and benefits of the present invention having beenstated, others will become apparent as the description proceeds whentaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a partial side sectional view of a prior art downhole system.

FIG. 2 is a partial side sectional view of a portion of the system ofFIG. 1.

FIG. 3 is a side sectional view of an embodiment of a downhole tool withan expandable sleeve.

FIG. 4 is side perspective view of an example of an expandable sleeve.

FIG. 5 is a side partial sectional view of a portion of the downholetool of FIG. 3.

While the invention will be described in connection with the preferredembodiments, it will be understood that it is not intended to limit theinvention to that embodiment. On the contrary, it is intended to coverall alternatives, modifications, and equivalents, as may be includedwithin the spirit and scope of the invention as defined by the appendedclaims.

DETAILED DESCRIPTION OF INVENTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theillustrated embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be through and complete, and willfully convey the scope of the invention to those skilled in the art.Like numbers refer to like elements throughout.

It is to be understood that the invention is not limited to the exactdetails of construction, operation, exact materials, or embodimentsshown and described, as modifications and equivalents will be apparentto one skilled in the art. In the drawings and specification, there havebeen disclosed illustrative embodiments of the invention and, althoughspecific terms are employed, they are used in a generic and descriptivesense only and not for the purpose of limitation. Accordingly, theinvention is therefore to be limited only by the scope of the appendedclaims.

Shown in a side partial sectional view in FIG. 3 is an example of adownhole acoustic logging system in accordance with the presentdisclosure. More specifically shown is a downhole logging tool 50inserted within a wellbore 52. The downhole tool 50 includes anelongated body 54 shown deployed in the wellbore 52 on wireline 56. Asurface truck 57 is shown for raising and lowering the downhole tool 50within the wellbore 52, the surface truck 57 may also include datarecording devices for recording data from within the wellbore 52. Thedownhole tool 500 f FIG. 3 also includes transducers 58, 60 housedwithin the body 54. Shown adjacent each of the transducers 58, 60 areopenings 64, 66 through the body 54 so that signals may communicate toand/or from the transducers 58, 60 to the outside of the downhole tool50. In the example of FIG. 3, the transducer 58 is an acoustictransmitter shown emitting an acoustic signal into the formation 62surrounding the wellbore 52. Also the transducer 60 illustrated is shownas a receiver for receiving acoustic signals reflected from or otherwisepropagating through the formation 62.

Boots 68, 70 are shown housed within the body 54 and covering openings64, 66. The boots 68, 70 may be formed from any type of elastomer orother pliable material that may be used for sealing and transmitting orcommunicating pressure. In the embodiment of FIG. 3, expandable sleeves72, 74 are shown included over the boots 68, 70. In this example, thesleeves 72, 74 may extend past the ends of the boots 68, 70. However,other arrangements are available wherein the sleeves 72, 74 cover aportion of the boot 68, 70; as well as configurations where multiplesleeves 72, 74 may be placed over a single boot 68, 70.

Shown in FIG. 4 is a side perspective view of an example of anexpandable sleeve 72, 74. The sleeve 72, 74 of FIG. 4 is made up of aseries of elongated members 76, where the members 76 may be a filament,a monofilament, or a braided line. The elongated members 76 of FIG. 4are illustrated as woven into a tubular-shaped configuration. The weaveof the element 76 is such that axial forces applied to opposing ends ofthe sleeve 72, 74 can elongate the sleeve 72, 74 and reduce the radiusof the sleeve 72, 74. Similarly, applying a force on the inside wall ofthe sleeve 72, 74 and directed radially outward from its axis A_(X) canreduce the length of the sleeve 72, 74 while increasing the diameter ofthe sleeve 72, 74. An example of material for the elongated member 76 isa polyetheretherketone (PEEK). The expandable sleeve 72, 74 may beobtained from Federal-Mogul Corporation, 26555 Northwestern Highway,South Field, Mich. 48033, Ph: 248-354-7700.

Shown in FIG. 5 is an example of a portion of the downhole tool 50 ofFIG. 3 being raised from within the wellbore 52. In this example,although lighter molecular weight fluids may have become trapped withinthe boot 68, 70, the sleeve 72, 74 covering the boot 68, 70 limitsoutward radial movement of the boot 68, 70, thereby maintaining apressure within the body 54 of the downhole tool 50. The increasedpressure can accelerate the escape of the trapped fluids within the boot68, 70 to permeate through the wall of the boot 68, 70 and to outside ofthe tool 50. Because outward bulging of the boot 68, 70 may result incontact against the wall of the wellbore 52; the expandable sleeve 72,74 can provide a protective layer between the boot 68, 70 and wall ofthe wellbore 52. Also, by limiting the boot 68, 70 from outwardlybulging through an adjacent opening 64, 66, the boot 68, 70 is lesslikely to grab or catch the wellbore wall, thus the expandable sleeve72, 74 better facilitates removal of the tool 50 from within thewellbore. The sleeve 72, 74 may also protect the boot 68, 70 duringmaintenance, since high pressure water is often used for cleaning thedownhole tool 50.

Referring back to FIG. 5, a clamp 78 is schematically illustrated foranchoring the expandable sleeve 72 and boot 68 within the downhole tool50. In the example of FIG. 5, the clamp 78 couples both the expandablesleeve 72 and boot 54 around a mandrel 80 in the downhole tool 68;wherein the mandrel 80 may also be used to secure the transducer 58. Theexpandable sleeve 72 and boot 54 may be the same or different lengths,but both are shown having a length exceeding that of the opening 64.

The present invention described herein, therefore, is well adapted tocarry out the objects and attain the ends and advantages mentioned, aswell as others inherent therein. While a presently preferred embodimentof the invention has been given for purposes of disclosure, numerouschanges exist in the details of procedures for accomplishing the desiredresults. These and other similar modifications will readily suggestthemselves to those skilled in the art, and are intended to beencompassed within the spirit of the present invention disclosed hereinand the scope of the appended claims.

1. A downhole tool comprising: a housing; a space in the housing; anopening formed through a sidewall of the housing; a barrier between theopening and the space comprising a membrane; and a series of elongatemembers arranged on a side of the membrane facing the opening, so thatwhen pressure in the space exceeds pressure ambient to the housing, themembers restrain the membrane from bulging through the space.
 2. Thedownhole tool of claim 1, further comprising a transducer within thehousing, wherein the transducer comprises a device selected from thegroup consisting of is an acoustic transmitter, an acoustic receiver,and combinations thereof.
 3. The downhole tool of claim 2, wherein thetransducer acoustically communicates from within the housing and throughthe membrane and the series of elongate members.
 4. The downhole tool ofclaim 1, wherein the barrier is formed from an elastomeric material andformed into a sleevelike configuration and wherein the elongate membersdefine a sleeve that circumscribes the barrier.
 5. The downhole tool ofclaim 3, further comprising a mandrel in the space and a couplinganchoring the sleeve and barrier to the mandrel.
 6. The downhole tool ofclaim 1, further comprising a plurality of openings from through thesidewall of the housing, a barrier between each of the openings and thespace, wherein each of barrier comprises a membrane, and a series ofelongate members on the surface of each membrane facing the opening. 7.The downhole tool of claim 1, wherein at least some of the elongatemembers intersect some of the other elongate members to define a mesh.8. A method of wellbore operations comprising: providing a downhole toolcomprising: a housing with an inside space, an opening through asidewall of the housing, and a barrier between the inside space and theopenings; applying a series of elongate members between the barrier andthe opening that are coupled with the tool, thereby shielding thebarrier from direct contact with a borehole wall when inserted into thewellbore and retaining the barrier within the housing when the pressurein the space exceeds pressure ambient to the housing and; deploying thedownhole tool in the wellbore.
 9. The method of claim 8, wherein theelongate members are arranged in a mesh-like configuration andintertwined to form a cohesive member.
 10. The method of claim 9,wherein the barrier and the cohesive member are tubular members, themethod further comprising clamping the barrier and cohesive member to amandrel within the housing.
 11. The method of claim 8, furthercomprising acoustically communicating from within the housing andthrough the barrier and elongate members.
 12. The method of claim 11,wherein the step of acoustically communicating comprises actuating atransducer within the housing, wherein the transducer comprises a deviceselected from the group consisting of is an acoustic transmitter, anacoustic receiver, and combinations thereof.